Control valve

ABSTRACT

A control valve including: a valve body, a flow shutter operatively interposed between an inlet and an outlet, a driving spindle having at least a first actuating end and a second end connected to the flow shutter. The valve also includes a differential pressure automatic regulation device, comprising: a cup-shaped body arranged around the driving spindle and axially mobile with respect to said driving spindle; a spring operatively interposed between the valve body and the cup-shaped body to push the latter away from the flow shutter; a rolling membrane having a radially inner edge fixed to the cup-shaped body and a radially outer edge fixed to the valve body to delimit a first chamber in fluid communication with the inlet and a second chamber in fluid communication with the outlet.

RELATED APPLICATIONS

This application is continuation of U.S. patent application Ser. No.14/898,451 filed Jan. 13, 2016 which is the U.S. national phase ofInternational Application No. PCT/IB2014/062109 filed Jun. 10, 2014,which designated the U.S. and claims priority to Italian PatentApplication MI2013A000973 filed Jun. 13, 2013, the entire contents ofeach of these applications are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a control valve. In particular, thepresent invention relates to a valve capable of guaranteeing a constantflow automatically, independently of any fluctuations in pressureupstream or downstream of the valve itself. Said valves are preferablyused in heating systems also of highly different dimensions, such ascentral heating systems in residential units or district heating systemscapable of supplying heat to entire districts and/or small towns, and/orcooling systems.

STATE OF THE ART

Control valves provided with membrane sensitive elements are knownwhich, on the basis of a differential pressure signal, regulate apassing port so as to maintain the differential pressure and the flowrate substantially constant as the incoming or outgoing pressure varies.

Said valve type is described, for example, in document EP 2 338 093 (WO2009/135490) and comprises a device adapted to maintain a constantdifferential pressure between an inlet and an outlet and a device forcontrol of the flow rate controlled by means of a pin connected to anactuator. The differential pressure device comprises a rolling membraneand a throttling element capable of placing itself in equilibrium underthe action of the incoming pressure, the outgoing pressure and the forceof a spring. The device for control of the flow rate comprises an innercylindrical shell and an outer cylindrical shell provided withrespective openings. Control of the flow rate is implemented through therotation of one shell with respect to the other such as to vary adelimited passage between the openings of said shells. Reduction of theflow rate is achieved by means of the joint axial movement of thecylindrical shells.

Public document AT413435 illustrates a flow regulation device comprisinga rotating type butterfly valve.

Document WO 2005/038315 is also known, which illustrates a regulationinsert for valves for control of the flow of liquid in heating orconditioning systems. The insert comprises a cup-shaped portion providedwith an inlet opening and an outlet opening wherein the outlet openingis closed in response to the differential pressure by means of theinsert and under the influence of a spring.

OBJECT OF THE INVENTION

The Applicant has observed that the valves of the prior art equippedwith automatic regulation and flow rate control, such as the onedescribed in document EP 2 338 093, are structurally highly complex andfor this reason also very expensive and cumbersome, precisely becausethey comprise various moving parts dedicated to the respectivefunctions.

The Applicant has also observed that said complexity impacts negativelyon regularity of the flow which passes through it, since the liquid mustnecessarily transit in tortuous conduits and/or flow over structuralelements, such as springs, with variable geometry or the configurationof which is not constant in all valve operating conditions.

In this field, the Applicant has therefore perceived the need to proposea control valve which:

presents a simpler and more linear structure than those of the priorart;

is more compact than the known valves;

guarantees greater cleaning and regularity of the flow passing throughit;

allows the flow rate to be set and controlled precisely;

ensures a fine and rapid automatic regulation of the differentialpressure and/or the flow rate.

SUMMARY OF THE INVENTION

The Applicant has found that said objectives may be obtained by means ofa control valve wherein the arrangement of the elements comprising it issuch that circulation of the liquid passing through it occurs inconduits, chambers and hollow spaces which are close to a centraldriving spindle and along directions which are mainly parallel to saidspindle.

More specifically, according to one aspect, the present inventionrelates to a control valve, comprising:

a valve body having an inlet and an outlet;

a flow shutter operatively interposed between the inlet and the outlet;

a driving spindle having a first actuating end and a second end oppositethe first end and connected to the flow shutter, wherein the drivingspindle develops along a principal axis;

a differential pressure automatic regulation device, comprising:

a cup-shaped body around the driving spindle and axially mobile withrespect to said driving spindle;

a spring operatively interposed between the valve body and thecup-shaped body to push said cup-shaped body away from the flow shutter;

a rolling membrane having a radially inner edge fixed to the cup-shapedbody and a radially outer edge fixed to the valve body so as to delimita first chamber in fluid communication with the inlet and a secondchamber in fluid communication with the outlet.

Preferably, the flow shutter has at least one inlet opening facing theinlet of the valve body and at least one outlet opening facing thecup-shaped body.

Preferably, the valve comprises a shutter mounted around the drivingspindle and facing the outlet opening of the flow shutter.

Preferably, the flow from the inlet enters the inlet opening of theshutter along a substantially radial direction and exits through theoutlet opening of said shutter along a substantially axial direction tothen transit towards the outlet of the valve along a substantiallyradial direction.

The Applicant has verified, in the first place, that the arrangement ofthe valve components according to what is described above and/or asclaimed allows the necessary passages for the fluid to be obtained witha simple and compact structure.

The Applicant has also verified that the valve according to theinvention guarantees greater cleaning and regularity of the flow whichpasses through it.

The Applicant has also verified that the valve according to theinvention allows the flow rate to be set and controlled with precision.

In conclusion, the Applicant has also verified that the valve accordingto the invention ensures a fine and rapid automatic regulation of thedifferential pressure and/or the flow rate.

The present invention can also have one or more of the preferredcharacteristics that are described herein below.

Preferably, the valve comprises a guide shaft having an axial passagefor the driving spindle, wherein the cup-shaped body is mounted aroundsaid guide shaft. In this manner, the axial movement of the cup-shapedbody, governed automatically by the differential pressure which acts onthe rolling membrane and on the cup-shaped body and by the spring whichacts directly on said cup-shaped body, is not influenced by any axialmovement of the driving spindle, since said two elements are decoupledfrom the interposed guide shaft. Said solution allows drastic reductionof the transients caused by dragging which the driving spindle exerts onvalves of the known type, such as the one described in EP 2 338 093, onthe respective cup-shaped body.

Preferably, the driving spindle may slide axially in the guide shaft.The guide shaft therefore performs its function as axial guide for thedriving spindle inside it.

Preferably, the cup-shaped body may slide axially on the guide shaft.Therefore, the guide shaft performs its function as axial guide for thecup-shaped body which slides around it.

Preferably, the guide shaft is fixed with respect to the valve body.More preferably, the guide shaft is an integral part of the valve body.Adopting this solution, the axial movement of the cup-shaped body is notinfluenced by the movement of other elements apart from the rollingmembrane and the spring.

Preferably, the spring is arranged around the cup-shaped body. Theposition of the spring is such as to reduce its dimensions to a minimumand it contributes to limiting the overall dimensions of the valve.

Preferably, a portion of the second chamber is delimited between aradially outer surface of the cup-shaped body and a radially innersurface of the valve body. Preferably, the spring is arranged in saidportion of the second chamber. The second chamber is therefore also usedto house the spring.

Preferably, in at least one operating condition of the open valve, theflow shutter and the shutter delimit between them an annular chambercommunicating laterally with the outlet of the valve body. The principalflow of the liquid exits axially from the flow shutter, flows in theannular chamber and exits through the outlet in a substantially radialdirection.

Preferably, the spring is axially offset with respect to the annularchamber. More preferably, the second chamber which contains the springis axially offset with respect to the annular chamber and in fluidcommunication with said annular chamber. The principal flow of theliquid is therefore not affected by the presence of the spring. Moregenerally, the liquid transits advantageously without encounteringelements with variable geometry, like the spring, which would influencethe flow differently as a function of its instantaneous configurationand would be subjected to undesired fluid-dynamic loads.

Preferably, the valve body has a cylindrical housing for the flowshutter. Preferably, the valve body has an outlet port between theannular chamber and the outlet. Preferably, the cup-shaped body, withits own axial motion, shuts said outlet port. Preferably, thecylindrical housing has a striking edge adapted to receive in abutment aterminal edge of the cup-shaped body so as to shut off the outlet portof the valve body. Preferably, the cylindrical housing has a strikingedge adapted to receive in abutment, in a closed valve condition, aperipheral edge of the shutter. Advantageously, on the same strikingedge both the shutter, in a radially more inner position, and thecup-shaped body, in a radially more outer position, engage.

Preferably, in a closed valve condition, the shutter substantiallyblocks the outgoing flow from the outlet opening of the shutter which itfaces. Preferably, the shutter cooperates with the cylindrical housingof the valve body to close the outlet opening of the flow shutter.

Preferably, the shutter is at least partially housed in the cup-shapedbody. Preferably, the cup-shaped body has a cylindrical wall radiallyoutside of the shutter and sliding mobile on said shutter. Thisgeometry, which uses the inner volume of the cup-shaped body to housethe shutter, contributes to limiting the overall dimensions of thevalve.

Preferably, the shutter closes an inner volume of the cup-shaped bodyand between the radially outer cylindrical wall of the cup-shaped bodyand the shutter a circular split is delimited which allows the fluid topass into said inner volume in order to exert a pressure (downstream oroutlet pressure) substantially equal to the pressure in the secondchamber and in contrast with the pressure in the first chamber (upstreamor inlet pressure).

Preferably, the shutter is solidly constrained to the driving spindle inthe rotation motion. Preferably, the shutter is solidly constrained tothe driving spindle in the axial movement. Preferably, the flow shutteris solidly constrained to the driving spindle in the rotation motion.Preferably, the flow shutter is solidly constrained to the drivingspindle in the axial movement. The driving mechanism is extremelysimple, since the driving spindle moves solidly with the flow shutterand/or with the shutter.

Preferably, the axial distance between the shutter and the flow shutteris fixed and they delimit between them a substantially toroidal volumewhich, when the valve is open and therefore the shutter is distancedfrom the striking edge of the cylindrical housing, it defines theaforesaid annular chamber and is in the same axial position as theoutlet port of the valve body. When the valve is closed, on the otherhand, said substantially toroidal volume is inserted in the cylindricalhousing and is isolated from the outlet of the valve body.

Preferably, the valve body has an inlet port between the inlet and theflow shutter. Preferably, the inlet port is a slot and is realiseddirectly on the valve body between the inlet and the flow shutter. Theinlet slot in the cylindrical housing of the valve body allows theelements of the valve to be reduced, since other walls between the valvebody and the flow shutter to change the cross-section of the flowpassage into said flow shutter are not necessary.

Preferably, the flow shutter is rotatable in the valve body on action ofthe driving spindle to change the position of its inlet opening withrespect to the inlet slot and to change a cross-section of the flowpassage. Said regulation is preferably performed manually and serves topre-set a reference flow rate.

Preferably, the flow shutter is axially mobile in the valve body onaction of the driving spindle to change the position of its inletopening with respect to the inlet port and to change a cross-section ofthe flow passage. Said regulation is preferably motorised and serves tomodulate the flow rate from a maximum value equal to the pre-setreference flow rate to zero, as a function of the thermal requirementsof the environment to be heated or cooled.

Preferably, the inlet opening of the flow shutter has a plurality ofwindows with calibrated cross-section with mainly axial development. Ina different embodiment, the inlet opening of the flow shutter has asingle window with calibrated cross-section with mainly axialdevelopment.

Preferably, said windows are slits which are parallel to the principalaxis.

Rotation of the flow shutter allows choice of the number of windowsand/or the cross-section of passage facing the inlet slot of the valvebody. Axial translation of the flow shutter allows regulation of thearea of the already facing windows.

In a different embodiment, said windows are slits which are inclinedwith respect to the principal axis, so as to obtain a flow shutter withlinear characteristics both in rotation and in translation (there is thesame percentage variation between the flow coefficient and the flowshutter position).

In a different embodiment, said windows are shaped to obtain anequal-percentage characteristic both in rotation and in translation (thesame percentage variation of the flow coefficient on the previous valuecorresponds with equal variations on absolute value of the position).Preferably, said windows have areas which are different from each other.Preferably, at least some of said windows each have a substantiallyarrow-shaped outline.

Preferably, the flow shutter comprises a radially outer cylindricalwall, a radially inner cylindrical wall and an annular-shaped base wallwhich connects said cylindrical walls. The radially outer cylindricalwall, the radially inner cylindrical wall and the base wall delimit aninner volume which leads into an annular outlet opening placed in anaxially opposite position to the base wall.

Preferably, the flow shutter comprises a single wide opening covered bya sheet or band in which said windows are afforded. Preferably, saidwindows are obtained in the sheet or band by means of photo-engravingand/or laser. Preferably, the sheet or band is applied to the singlewide opening after affording the windows. This solution allows windowswith even highly complex outlines to be afforded in the sheet, since itmay be worked flat, and then the sheet may be applied to the flowshutter.

Preferably, the flow shutter has a rotation limiter cooperating with thevalve body. Preferably, the rotation limiter is an appendage of the flowshutter inserted in a small chamber afforded in the valve body. Thenon-circular shaped wall of the small chamber allows limited rotation ofthe appendage. The rotation limiter serves to delimit the positionswhich correspond with the minimum and the maximum possible regulations.

Preferably, the driving spindle has an axial conduit adapted to placethe inlet in fluid communication with the first chamber. Preferably, achannel afforded in the valve body connects the inlet with a smallchamber located in the flow shutter and into which the axial conduitleads. Preferably, the driving spindle has radial passages in fluidcommunication with the axial conduit and leading onto its own radiallyouter surface. Preferably, the guide shaft has radial passages adaptedto place the radial passages of the driving spindle in fluidcommunication with the first chamber. Preferably, the radial passages ofthe guide shaft communicate with a hollow space delimited between theguide shaft and the cup-shaped body in turn communicating with the firstchamber. The pressure of the incoming fluid is thus transmitted to thefirst chamber which is placed in an axially opposite position withrespect to the flow shutter.

Preferably, the valve comprises a principal spring interposed betweenthe driving spindle and the valve body to maintain the valve open in theabsence of forces applied on the first end of the driving spindle.

Preferably, the valve comprises an actuator which is operatively activeon the first end of the driving spindle. Preferably, the actuator movesthe driving spindle and the flow shutter axially. Preferably, the valvecomprises a regulating ring nut mounted at the first end of the drivingspindle to set manually the angular position of the flow shutter. Theactuator allows modulation of the flow rate from a maximum value equalto the reference flow rate pre-set with the ring nut to zero (shutterclosed).

Preferably, the valve comprises a first pressure intake in fluidcommunication with the inlet and a second pressure intake in fluidcommunication with the outlet. Preferably, the pressure intakes arearranged on opposite sides of the actuator. Preferably, the pressureintakes are inclined with respect to the principal axis.

In a different embodiment, they are alongside and parallel to each otherand also preferably parallel to the principal axis and/or perpendicularto the direction of flow along which the inlet and outlet are aligned.Preferably, the pressure intakes are placed on the opposite side to theactuator with respect to the direction along which the inlet and outletare aligned.

Further characteristics and advantages of a preferred, but notexclusive, embodiment of a control valve according to the presentinvention will appear more clearly from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

This description will be explained below with reference to the attacheddrawings, provided solely for indicative and therefore non-limitingpurposes, in which:

FIG. 1 shows an overall perspective view of the control valve accordingto the present invention;

FIG. 2 shows a cross-section view of the valve of FIG. 1, with severalparts removed and in an operating configuration;

FIG. 3 shows an enlarged and cross-section portion of the valve of FIGS.1 and 2;

FIG. 4 shows the valve of FIG. 2 in a different operating configuration;

FIG. 5 shows the valve of FIG. 2 in a further different operatingconfiguration;

FIG. 6 shows an overall perspective view of a variant of the controlvalve according to the present invention;

FIG. 7 shows a cross-section view of the valve of FIG. 6, with severalparts removed and in an operating configuration;

FIG. 8 shows an embodiment of an exploded detail relating to the valvesof the previous figures;

FIG. 9 shows a variant of an element shown in FIG. 8;

FIG. 10 shows a different embodiment of the detail of FIG. 8.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

With reference to FIG. 1, the number 1 denotes in its entirety a controlvalve comprising a valve body 2 and an actuator 3 mounted on the valvebody 2. The valve body 2 has an inlet 4 and an outlet 5 for flow of aliquid. Said inlet 4 and outlet 5 are threaded internally for connectionto respective pipe ends.

As visible in FIGS. 2, 4 and 5, the valve body 2 has a principal body 2a afforded in a single piece and having said inlet 4 and said outlet 5aligned along a flow direction “Y-Y”. The valve body 2 comprises anauxiliary body 2 b screwed onto the principal body 2 a and having anaxial passage 6 which develops along a principal axis “X-X”. Theprincipal body 2 a of the valve body 2 delimits internally, in additionto the inlet 4 and to the outlet 5, a substantially cylindrical cavitywhich develops along said principal axis “X-X” and is formed by severalaxial cross-sections, as detailed here below. In the embodiment shown,the principal axis “X-X” is perpendicular to the flow direction “Y-Y”.In variants not shown, the angle delimited between said principal axis“X-X” and the flow direction “Y-Y” may be different to 90°.

The valve body 2 also has pressure intakes 101, 102 for housing and/orconnection with appropriate pressure sensors and/or differentialpressure gauges. A first pressure intake is in fluid communication withthe inlet 4 and a second pressure intake is in fluid communication withthe outlet 5. Said intakes 101, 102 are inclined with respect to theprincipal axis “X-X” and also with respect to the flow direction “Y-Y”and are placed on opposite sides of the auxiliary body 2 b and theactuator 3.

Starting from a first axial end “E1” of the valve body 2 opposite theauxiliary body 2 b and moving towards a second axial end “E2” at saidauxiliary body 2 b, the substantially cylindrical cavity has a firstsection 7, a second section 8 of higher radial dimensions to the firstsection 7, a third section 9 of higher radial dimensions to the secondsection 8 and a fourth section 10 of higher radial dimensions to thethird section 9.

The first section 7 defines a small chamber connected to the inlet 4through a straight channel 11 afforded in the principal body 2 a. Thesecond section 8 defines a cylindrical housing placed between the inlet4 and the outlet 5 and in direct communication with the inlet 4 throughan inlet slot 12 afforded in a wall of the valve body 2 which delimitssaid cylindrical housing. The inlet slot 12 has an elongated developmentalong a circumferential direction. The third section 9 and the fourthsection 10 define together a cylindrical seat. The third section 9 alsohas an outlet port 13 which communicates directly with the outlet 5 ofthe valve body 2.

A driving spindle 14 is inserted in the axial passage 6 of the auxiliarybody 2 b and develops in said substantially cylindrical cavity of theprincipal body 2 towards the first axial end “E1”. A first actuating end14 a of the driving spindle 14 projects from the auxiliary body 2 b anda second end 14 b of said driving spindle 14, opposite the first end 14a, is placed inside the cylindrical housing 8 and facing the smallchamber 7 (FIGS. 3 and 5).

Inside the auxiliary body 2 b and around the driving spindle 14 isdelimited a volume 15 containing a principal spring 16 of helical typewhich surrounds the driving spindle 14.

The principal spring 16 has an end in abutment against an annularsurface of the auxiliary body 2 b and an opposite end in abutmenteagainst a ring 17 axially solid with the driving spindle 14 and, forthis purpose, partially inserted in an annular cavity afforded at thefirst end 14 a of the driving spindle 14. The first end 14 a is alsocoupled to an actuating group “D” engaged by the actuator 3. Theprincipal spring 16 elastically pushes the driving spindle 14 away fromthe first axial end “E1” of the valve body 2.

A flow shutter 18 is mounted on the second end 14 b of the drivingspindle 14 and is housed in the cylindrical housing 8 (FIGS. 3 and 5).The flow shutter 18 comprises a radially outer cylindrical wall 19, aradially inner cylindrical wall 20 and an annular-shaped base wall 21which connects said cylindrical walls 19, 20. The radially outercylindrical wall 19, the radially inner cylindrical wall 20 and the basewall 21 delimit an inner volume 22 which leads into an annular outletopening 23 placed in an axially opposite position to the base wall 21.Through the radially outer cylindrical wall 19 is afforded an inletopening formed by a plurality of windows 24 reciprocally facing along acircumferential direction and each having a mainly axial development.The radially outer cylindrical wall 19 is placed in contact with thecylindrical housing 8 with interposition of annular seals. The radiallyinner cylindrical wall 20 surrounds and is placed in contact, withinterposition of seals, with the driving spindle 14. The flow shutter 18is blocked on the driving spindle 14 so as to remain solidly constrainedwith it in both axial motion and in rotation around the principal axis“X-X”. The flow shutter 18 also comprises an appendage 25 which developsaxially from a radial edge close to the base wall 21 and remains in thesmall chamber 7. The appendage 25 interferes with a non-circular shapedwall which delimits the small chamber 7 and acts as a rotation limiterfor the flow shutter 18.

A shutter 26 is mounted around the driving spindle 14 and is blocked onthe driving spindle 14 so as to remain solidly constrained with it inboth axial motion and in rotation around the principal axis “X-X”. Theshutter 26 comprises a circular plate 27 and a shaped portion 28,preferably in rubber, substantially tapered and associated with theplate 27 and facing the outlet opening 23 of the flow shutter 18. Theshutter 26 and the flow shutter 18 are solidly constrained to each otherin the axial movement and in the rotation movement. Therefore, the axialdistance between the shaped portion 28 of the shutter 26 and the outletopening 23 of the flow shutter 18 is fixed. In particular, thesubstantially tapered shaped portion 28 has two successive taperedportions converging towards the driving spindle 14 and towards saidoutlet opening 23. The shutter 26 and the flow shutter 18 delimitbetween them a substantially toroidal volume towards which the outletopening 23 of the flow shutter 18 opens. The shaped portion 28 of theshutter 26 has a radially peripheral edge 29 destined to enter intocontact with a striking edge 30 of the cylindrical housing 8 orthogonalto the principal axis “X-X” and defined between the second section 8 andthe third section 9 of the substantially cylindrical cavity of theprincipal body 2 a.

A cup-shaped body 31 is mounted around the driving spindle 14 and isaxially positioned in the cylindrical seat defined by the third section9 and the fourth section 10. In greater detail, the cup-shaped body 31has an axial hole through which passes a guide shaft 32 defined by aninner portion of the auxiliary body 2 b. Said axial passage 6 of theauxiliary body 2 b is partially afforded in the guide shaft 32 so thatsaid guide shaft 32 remains radially interposed between the drivingspindle 14 and the cup-shaped body 31. The cup-shaped body 31 has afirst portion 33 with lower radial dimensions coupled sliding to theguide shaft 32 with interposition of an annular seal preferably placedin an annular seat of said guide shaft 32. The cup-shaped body 31 has asecond portion 34 with higher radial dimensions such as to house theshutter 26 inside it. A terminal edge 35 (FIG. 3) of the second portion34 of the cup-shaped body 31 is destined to enter into striking contactwith a striking edge 30 of the cylindrical housing 8 in a radially moreouter zone with respect to the striking zone of the shutter 26. Thecup-shaped body 31 has a radially outer annular appendage 36 axiallyplaced between the first portion 33 and the second portion 34. A helicalspring 37 is arranged around the cup-shaped body 31 and has an axial endplaced in striking contact against said annular appendage 36 and anopposite axial end in abutment against an abutment surface 38 definedbetween the third section 9 and the fourth section 10 of thesubstantially cylindrical cavity of the principal body 2 a.

A rolling membrane 39 surrounds the cup-shaped body 31 and has aradially inner edge 40 sealingly constrained to said cup-shaped body 31,preferably placed in a radially outer annular seat, and a radially outeredge 41 sealingly constrained to the valve body 2, preferably closedbetween the principal body 2 a and the auxiliary body 2 b. The rollingmembrane 39 delimits, together with the inner walls of the valve body 2and precisely the auxiliary body 2 b, a first chamber 42 axially placedbetween the cup-shaped body 31 and the auxiliary body 2 b. The rollingmembrane 39 also delimits, together with a radially outer surface of thecup-shaped body 31 and a radially inner surface of the principal body 2a, a second chamber 43 axially placed between said membrane 39 and theabutment surface 38. The spring 37 thus remains placed in a portion ofsaid second chamber 43. The cup-shaped body 31 is mobile axially in anindependent way from the guide shaft 14 and therefore also from theshutter 26 and from the flow shutter 18 under the action of thepressures acting in the first chamber 42 and in the second chamber 43and of the spring 37. The cup-shaped body 31 with its axial movement isable to shut off or close the outlet port 13.

The cup-shaped body 31, the rolling membrane 39 and the spring 37 arepart of a differential pressure automatic regulation device, as will bedetailed below.

The shutter 26 closes an inner volume 44 of the cup-shaped body 31 whichis substantially at the same pressure of the second chamber 43 becausebetween a radially inner surface of the radially outer cylindrical wall43 of the cup-shaped body 31 and a peripheral edge of the plate 27 acircular split 45 (FIG. 3) remains through which the liquid passes. Saidinner volume of the cup-shaped body 31 is variable due to the relativemotion possible between said cup-shaped body 31 and the shutter 26.

In use and with the valve open (FIGS. 2 and 4), the flow of liquidenters into the inlet 4, passes through the inlet slot 12 and theportion/s of the window/s 24 of the inlet opening of the flow shutter 18facing said slot 12 and enters into the inner volume 22. The liquidrises axially towards the outlet opening 23 of the flow shutter 18reaching an annular chamber delimited by the flow shutter 18, by theshutter 26 and by radially inner surfaces of the third section 9 and thesecond section 8 of the substantially cylindrical cavity of theprincipal body 2 a. The principal flow of the liquid then continuestowards the outlet 5 passing through the outlet port 13.

The flow rate is pre-set by rotating the flow shutter 18 by means of thedriving spindle 14 in a pre-selected angular position, so that aspecific number of windows 24 are facing the inlet slot 12. Rotation isperformed manually by means of a regulating ring nut 51 mounted on thefirst end 14 a of the driving spindle 14. The ring nut 51 may be reachedby dismantling the actuator 3. During functioning of the valve 1, saidangular position remains fixed.

The liquid in the inlet 4 is at a specific upstream pressure “P+”. Inpassage through the flow shutter 18 and due to the resistances givenboth by the flow shutter 18 and by the shutter 26, the liquid suffers adrop in pressure down to a downstream pressure “P−” which is in theannular chamber 46 and substantially also at the outlet 5.

The liquid at upstream pressure “P+” is also present in the firstchamber 42 because from the inlet 4 it passes into the straight channel11, into the small chamber 7, through an axial conduit 47 afforded inthe driving spindle 14, through radial passages 48 of said spindle 14,through radial passages 49 of the guide shaft 32 and through a hollowspace 50 delimited between the guide shaft 32 and the cup-shaped body 31which in turn communicates with the first chamber 42 (FIG. 3).

The liquid at downstream pressure “P−” is also present in the secondchamber 43 because from the annular chamber 46 it passes into the secondchamber 43 through an annular passage delimited between the cup-shapedbody 31 and a radially inner surface of the principal body 2 a close tothe abutment surface 38. The liquid at downstream pressure “P−” is alsopresent in the inner volume of the cup-shaped body 44 because it passesthrough the circular split 45.

Therefore the upstream pressure “P+” acts in the first chamber 42 on therolling membrane 39 and on the cup-shaped body 31 and the downstreampressure “P−” acts in the second chamber 43 and in the inner volume ofthe cup-shaped body 44 on said cup-shaped body 31 and partly also on themembrane 39. A force on the cup-shaped body 31 corresponds with upstreampressure “P+” directed from the second end “E2” towards the first end“E1”. A force on the cup-shaped body 31 corresponds with downstreampressure “P−” directed from the first end “E1” towards the second end“E2” which adds up to the force generated by the spring 37.

The equilibrium of the force generated by the upstream pressure “P+”with the one generated by the downstream pressure “P−” increased by theelastic reaction of the spring 37 changes the position of the cup-shapedbody 31 and the amplitude of the outlet port 13, guaranteeing continualconstancy of the flow rate automatically. In the absence of differentialpressure, the spring 37 maintains the cup-shaped body 31 in the positionclosest to the second end “E2” and the outlet port 13 completely open.

A modulation of the flow rate may also be made, around the flow ratepre-set manually, by axially moving the driving spindle 14 by means ofthe actuator 3. In FIG. 2, there are windows 24 facing for their entireaxial development the inlet slot 12. On the other hand, in FIG. 4 thewindows 24 are shifted closer towards the first end “E1” and partiallyclosed by the wall of the principal body 2 a adjacent to the inlet slot12. Axial movement of the spindle also determines, as visible fromcomparison between FIGS. 2 and 4, a variation in axial development ofthe annular chamber 46.

FIG. 5 shows the valve 1 closed, i.e. with the shutter 26 in abutmentagainst the striking edge 30 of the cylindrical housing 8. Said positionis maintained by the actuator 3 which pushes the spindle 14 in contrastwith the principal spring 16. Without the actuator 3, the principalspring 16 maintains the valve 1 in the normally open condition with theshutter 26 distanced from the striking edge 30.

FIGS. 6 and 7 show a different embodiment of the valve according to theinvention. The same reference numbers already used in FIGS. 1-5 toidentify corresponding elements have been used. Unlike the embodimentdescribed above, the valve of FIG. 6 has the pressure intakes 101, 102positioned on the opposite part of the actuator with respect todirection “Y-Y” along which are aligned the inlet 4 and the outlet 5 andare parallel to each other and also parallel to the principal axis“X-X”.

Furthermore, as visible in FIG. 7, in a radially intermediate positionbetween the cup-shaped body 31 and the principal body 2 a a cylindricalbody 110 coaxial to the principal axis “X-X” is positioned. An upperedge 111 of the cylindrical body 110 is closed between the auxiliarybody 2 b and the principal body 2 a and the radially outer edge 41 ofthe rolling membrane 39 is sealingly constrained between said upper edge111 and the auxiliary body 2 b. With respect to the embodiment of FIGS.1-5, the radially outer edge 41 and the overall rolling membrane 39 areshifted closer towards the first end 14 a of the driving spindle 14. Alower edge 112 of the cylindrical body 110 extends radially towards theprincipal axis “X-X” to define the abutment surface 38 of the spring 37which therefore, differently to the embodiment of FIGS. 1-5, does notbelong to the principal body 2 a. The cup-shaped body 31 is also shiftedcloser towards the first end 14 a of the driving spindle 14 and has alower cylindrical appendage 120 having the terminal edge 35 destined toabut against the striking edge 30.

The embodiment of FIGS. 6 and 7 also allows a greater volume of thesecond chamber 43 which is at discharge pressure “Pdischarge” to beobtained. The second chamber 43 is in this case radially delimitedbetween the cup-shaped body 31 and the cylindrical body 110 and betweensaid cylindrical body 110 and the principal body 2 a.

In the embodiment of FIG. 7, the presence of the terminal edge 35 of thelower cylindrical appendage 120, which remains radially distanced fromthe principal body 2 a, ensures that the downstream pressure “P−” in theannular chamber 46 is different to and higher than the dischargepressure “Pdischarge” at outlet 5.

In the embodiment of FIGS. 6 and 7, the windows 24 are splits inclinedwith respect to the principal axis “X-X”.

FIG. 8 shows an exploded view of a variant of the flow shutter 18 of theembodiment of FIGS. 6 and 7. The radially outer cylindrical wall 19 isprovided with a single wide opening 130 which extends partially aroundthe principal axis “X-X”, which is covered and closed by a sheet or band140 (shown separate in FIG. 8). The sheet 140 has slits 24 almost allinclined. In particular, sheet 140 has a first end slit 24 a parallel tothe principal axis “X-X”, a second slit 24 b adjacent to the first slit24 a and the remaining slits 24 having all the same inclination greaterthan the one of the second slit 24 b. Slits 24 a, 24 b, 24 are affordedin the sheet 140, for example by means of photo-engraving and/or laser,and then said sheet 140 is applied onto the opening 130.

FIG. 9 shows a variant of the sheet 140 wherein the windows 24 c, 24 d,24 e are shaped to give the flow shutter 18 an equal-percentagecharacteristic both in rotation and in translation.

FIG. 10 shows a further variant of the flow shutter 18, wherein saidflow shutter 18 is a single piece (like the one shown in FIGS. 1-5,without distinction between the sheet and the rest of the body), but thewindows 24 are shaped as in FIG. 9.

In a further embodiment not shown, the flow shutter 18 is a single pieceand the windows 24 are inclined slits as in FIG. 7.

Windows 24 c, 24 d, 24 e of FIGS. 9 and 10 comprise a first window 24 c(visible in both FIGS. 9 and 10) elongated along a circumferentialdirection and having a substantially arrow-shaped outline which ends atan end with a single top and at an opposite end with two tops axiallydistanced from each other. A second window 24 d (more visible in FIG. 9)is alongside the first window 24 c and also has a substantiallyarrow-shaped outline, but with lower passage area and circumferentialextension with respect to the first window 24 c. A third window 24 d(more visible in FIG. 9) is alongside the second window 24 d and has asubstantially isosceles triangular outline with the base which developsalong a circumferential direction.

List of elements  1 Control valve  2 Valve body E1 First axial end ofthe valve body E2 Second axial end of the valve body  2a Principal body 2b Auxiliary body X-X Principal axis of the valve body  3 Actuator  4Inlet  5 Outlet Y-Y Flow direction  6 Axial passage  7 Firstsection/small chamber  8 Second section/cylindrical housing  9 Thirdsection/cylindrical seat 10 Fourth section/cylindrical seat 11 Straightchannel 12 Inlet slot 13 Outlet port 14 Driving spindle  14a First endof the driving spindle  14b Second end of the driving spindle 15 Volume16 Principal spring 17 Ring 18 Flow shutter 19 Radially outercylindrical wall 20 Radially inner cylindrical wall 21 Base wall 22Inner volume 23 Outlet opening 24 Inlet opening 25 Appendage/rotationlimiter 26 Shutter 27 Plate 28 Shaped portion 29 Radially peripheraledge 30 Striking edge 31 Cup-shaped body 32 Guide shaft 33 First portion34 Second portion 35 Terminal edge 36 Annular appendage 37 Spring 38Abutment surface 39 Rolling membrane 40 Radially inner edge 41 Radiallyouter edge 42 First chamber 43 Second chamber 44 Inner volume of thecup-shaped body 45 Circular split 46 Annular chamber 47 Axial conduit 48Spindle radial passages 49 Guide shaft radial passages 50 Hollow space51 Regulation ring nut 101  First pressure intake 102  Second pressureintake 110  Cylindrical body 111  Upper edge of the cylindrical body112  Lower edge of the cylindrical body 120  Lower cylindrical appendageof the cup-shaped body 130  Wide opening of the radially outercylindrical wall 140  Sheet or band  24a First slit  24b Second slit 24c First window  24d Second window  24e Third window

1.-18. (canceled)
 19. A control valve comprising: a valve body having aninlet and an outlet; a flow shutter operatively interposed between theinlet and the outlet; a driving spindle having a first actuating end anda second end opposite the first actuating end and connected to the flowshutter, wherein the driving spindle extends along a principal axis; adifferential pressure automatic regulation device comprising: acup-shaped body around the driving spindle and axially mobile withrespect to the driving spindle; a spring operatively interposed betweenthe valve body and the cup-shaped body and configured to push thecup-shaped body away from the flow shutter; and a rolling membranehaving a radially inner edge fixed to the cup-shaped body and a radiallyouter edge fixed to the valve body to delimit a first chamber in fluidcommunication with the inlet and a second chamber in fluid communicationwith the outlet; wherein the flow shutter has at least one inlet openingfacing the inlet of the valve body and at least one outlet openingfacing the cup-shaped body; and wherein the control valve furthercomprises a shutter mounted around the driving spindle and facingtowards the outlet opening of the flow shutter.
 20. The control valveaccording to claim 19, further comprising a guide shaft having an axialpassage for the driving spindle, wherein the cup-shaped body is mountedaround the guide shaft.
 21. The control valve according to claim 20,wherein the guide shaft is fixed with respect to the valve body.
 22. Thecontrol valve according to claim 19, wherein the spring is arrangedaround the cup-shaped body.
 23. The control valve according to claim 19,wherein the second chamber houses the spring.
 24. The control valveaccording to claim 19, wherein a portion of the second chamber isdelimited between a radially outer surface of the cup-shaped body and aradially inner surface of the valve body, wherein the spring is arrangedin the portion of the second chamber.
 25. The control valve according toclaim 19, wherein, in at least one operating condition of the openvalve, the flow shutter and the shutter delimit between them an annularchamber communicating laterally with the outlet of the valve body. 26.The control valve according to claim 25, wherein the spring is axiallyoffset with respect to the annular chamber.
 27. The control valveaccording to claim 25, wherein a portion of the second chamber isdelimited between a radially outer surface of the cup-shaped body and aradially inner surface of the valve body, wherein the spring is arrangedin the portion of the second chamber, wherein the second chamber whichcontains the spring is axially offset with respect to the annularchamber.
 28. The control valve according to claim 19, wherein the valvebody has a cylindrical housing for the flow shutter, wherein the valvebody has an outlet port between the annular chamber and the outlet andwherein the cup-shaped body, with its axial motion, shuts off the outletport and wherein the cylindrical housing has a striking edge adapted toreceive in abutment a terminal edge of the cup-shaped body to close theoutlet port of the valve body.
 29. The control valve according to claim19, wherein the valve body has a cylindrical housing for the flowshutter and wherein the cylindrical housing has a striking edge adaptedto receive in abutment, with the valve closed, a peripheral edge of theshutter.
 30. The control valve according to claim 19, wherein, with thevalve closed, the shutter blocks a flow outgoing from the outlet openingof the flow shutter which faces the shutter.
 31. The control valveaccording claim 19, wherein the shutter is at least partially housed inthe cup-shaped body.
 32. The control valve according claim 19, whereinthe cup-shaped body has a cylindrical wall radially outside of theshutter and sliding mobile on the shutter.
 33. The control valveaccording claim 19, wherein the shutter closes an inner volume of thecup-shaped body and between the radially outer cylindrical wall of thecup-shaped body and the shutter a circular split is delimited whichallows the fluid to pass into the inner volume.
 34. The control valveaccording to claim 19, wherein the shutter is solidly constrained withthe driving spindle in rotation motion and in axial movement and whereinthe flow shutter is solidly constrained with the driving spindle in therotation motion.
 35. The control valve according claim 19, wherein aninlet slot is realized directly on the valve body between the inlet andthe flow shutter.
 36. The control valve according to claim 35, whereinthe flow shutter is rotatable in the valve body on action of the drivingspindle to change the position of its inlet opening with respect to theinlet slot.
 37. The control valve according to claim 19, wherein theshutter comprises a circular plate and a shaped portion in rubber,substantially tapered, associated with the circular plate and facing theoutlet opening of the flow shutter.
 38. The control valve according toclaim 19, wherein the inlet opening of the flow shutter has one or morewindows.
 39. A control valve comprising: a valve body including aninlet, an outlet and a flow passage extending from the inlet to theoutlet; a flow shutter in the flow passage and between the inlet and theoutlet, wherein the flow shutter includes an inlet opening facing theinlet of the valve body and an outlet opening facing a cup-shaped body;a driving spindle mounted in the valve body and extending perpendicularto a centerline of the flow passage, wherein the driving spindleincludes a first actuating end and a second end opposite the firstactuating end, wherein the second end is connected to the flow shutter;a shutter mounted to the driving spindle and facing towards the outletopening of the flow shutter, and a differential pressure automaticregulation device comprising: the cup-shaped body coaxial with andextending around the driving spindle and configured to move axially inthe valve body with respect to the driving spindle; a coil springbetween the valve body and the cup-shaped body, being coaxial to the cupshaped body, and biasing the cup-shaped body away from the flow shutter;and an annular rolling membrane having a radially inner edge fixed tothe cup-shaped body and a radially outer edge fixed to the valve body,wherein the annular rolling member separates a first chamber which is influid communication with the inlet from a second chamber which is influid communication with the outlet.